Flat ground markers at the rule of thumb today in a lot of Los Angeles cemeteries because they are ground maintenance friendly. My Armenian friends who have loved ones buried at Grand View Memorial Park have told me that they chose that cemetery because they were allowed to place culturally traditional monuments there.
Another cemetery that has flexible memorial rules is Hollywood Forever Cemetery. Some memorials there are gigantic, dwarfing the modest neighboring stones placed there upwards of 100 years earlier. Rumor has it that the larger the monument, the more a deceased person was loved.
But for the most part, the newer markers cover individual graves. I think they are just gorgeous and I particulary appreciate the added personal touch of portraits of the deceased engraved on the marble. Overall, they add diversity to the cemetery and forever reflect the changing demographics of the community, which I think will be of interest to future generations of grave hunters and historians.
One place within Hollywood Forever where you can see the stark difference between the past and the present is near the entrance. Driving in on Aizen Drive, just past Trierweiler Way and looking to your left you see this area of Section 13: